Bimmerfest - BMW Forums

Bimmerfest - BMW Forums (
-   E63 / E64 6 Series (2004 - 2010) (
-   -   Odd rough idle / rough drive (

sharkyclark 11-19-2012 02:36 AM

Odd rough idle / rough drive
Hiya All,

I have an issue with my '04 645ci.

After a prolonged period of not having driven it, say overnight, or following a day's work, I'll get in the car and start it up. The idle can be very rough (sometimes I am shaking in my seat), and the engine fault / catalytic converter error message comes up. I usually then drive the car (and it is rough) for a minute or two, then at a roundabout or traffic light I turn off the car, then turn it on again, after which it is a hell of a lot smoother. Odd that the engine restart would make such a difference. Then again I know little about cars. There are times however I am pushing it on the motorway and it still feels a bit rough and once I had the engine fault / cat error whilst going at the speed limit if you know what I mean.

Given that I am a newbie at maintaining my own car, could anyone give me a list of simple things I could check first before I hand over the PIN to my bank account to BMW...?

So advice appreciated!

(The other issues I have are an oil leak but I keep it topped up regularly until I am going to get it fixed, a slow coolant leak which I also keep topped up regularly until I get it fixed, and a gear 5 slippage when I keep the accelerator pressed down through gear changes which isn't a priority. So none of these should be related. Also a new battery was fitted recently and I had a new alternator put in not too long ago, so I think the power situation is in good order.)

P.S. Michael UK could you pls get in touch?



FredoinSF 11-19-2012 10:47 AM

Have your battery tested is first thing to do. Weird things happen when battery is weak.
These cars drain the battery sitting still. You need to go for a good long drive on a regular basis or hook the car to a battery tender.
If you replace the battery, it has to be "registered" to the car. If not the car will not know a new battery is in and it will overcharge the new battery resulting in potential damage and early replacement.

sharkyclark 11-20-2012 02:35 AM


If only that were the case!

...Also a new battery was fitted recently and I had a new alternator put in not too long ago, so I think the power situation is in good order....

New battery was just fitted. Also I drive the beast around 30,000 miles per year, and usually to the speed limit on motorways if you know what I mean.

Since the new battery, there has been no change in the issue. But over time it is noticeably getting worst...


HerbP 11-20-2012 08:00 PM

You could try disconnecting the battery for 30 minutes or longer, to see if this might help reboot all systems. Another thing to do to find hidden codes, is have someone run BMW diagnostics for codes that will not show up on handheld OBD2 code readers! A canister purge valve could be causing your problems, among other things.

Good Luck!

sharkyclark 11-29-2012 06:49 AM

Hi All,

To give you an update, the car is booked in next week to a specialist, so we'll see what is up.

The rough idle / rough running is so bad now, that even turning the car off / on again doesn't help as much as it used to. Oddly when it is running up to 60mph after engine restart it is generally smooth, but between 60-80mph very rough, and then 80+mph smooth again.

There is also a serious oil leak that needs fixing that will probably require engine removal.

The specialist said they may be related but who knows until he has had a look.

One thing is for sure, if I am going to keep this baby, I better learn how to do more myself, otherwise it will bankrupt me.



sharkyclark 11-29-2012 07:20 AM

Actually I am slowly learning stuff. I just read my codes using a code reader:

From Peake Research R5 code reader Table 22 :-
278d - Temp sensor coolant temp
274e - Misfire detection checksum failure
2748 - Misfire detection cylinder 7
2749 - Misfire detection cylinder 2

coupled with the symptoms right now:
a. Rough idle, rough running at certain speeds / times. Engine switch off/on again usually helps to smoothen it a bit but not completely
b. Oil leak (requiring stripping engine down, say BMW)
c. Slow coolant leak apparently, (from inside engine say BMW)

Next steps anyone, which a newbie like me might be able to perform?

Mulchman 11-29-2012 08:05 AM

I would start with coils and plugs as possible causes of the misfires.

If you've never replaced your plugs, they should probably be done. There are plenty of DIY's if you want to give it a shot yourself. Not too difficult, but the rear two are supposed to be a bit of a challenge.

For the coils, just figure out which cylinders are 7 and 2 (quick search online). Then swap the coils from other (no error) cylinders, clear the codes and drive till the codes come back. If the misfires move to the cylinders where the suspect coils are, then you've solve your problem (or at least one of them). This should be very easy and cost you nothing. Probably the first thing to do. If the codes remain on the same cylinder then replace (at least) those two plugs, clear codes and drive till they come back. This will elliminate some potential problems that are related to basic maintainance anyway.

Hope this helps...

sharkyclark 11-29-2012 09:02 AM

Thanks Mulchman! I had discussed doing that very procedure (swapping coils around) to see if the issue follows potentially bad coils. I'll give this a go first. I'll do it this weekend and report how I get on.

One thing is for sure, if I can save $$$ by doing something myself, my wife will start talking to me again. The car has become a major source of contention!

In the meantime I will see what else I can glean from the forum by searching further.



Mulchman 11-29-2012 12:26 PM


Originally Posted by sharkyclark (Post 7221023)
Thanks Mulchman! I had discussed doing that very procedure (swapping coils around) to see if the issue follows potentially bad coils. I'll give this a go first. I'll do it this weekend and report how I get on.

One thing is for sure, if I can save $$$ by doing something myself, my wife will start talking to me again. The car has become a major source of contention!

In the meantime I will see what else I can glean from the forum by searching further.



Understood! A home theater forum I used to go on called it the WAF (Wife Acceptance Factor) :bustingup

For that matter you could also swap some plugs to save $$$ during your diagnostics. Might help you buy only what is needed now.

gebhardt 12-02-2012 05:51 AM

I know this may be dismissed but this is a 99% certainty here, maybe more, and i'm afraid its not good news at all

On these engines the intermediate levers for the valvetronic system are prone to wearing out

This means that you won't get the full travel of the levers which in turn affects the valve lift and therefore running of the engine. It seems to cause more issues at idle from stone cold than anything else.

Any cars with an issue or starting to have an issue will run very poor from a cold start and more often than not throw a management light. Code reading will show up multiple misfires on each cylinder as has happened with yourself.

Usually with cars that are just starting to exhibit these symptoms, after about 30 seconds or so, the idle will smooth out and the car will run fine for the remainder of the day and at subsequent starts. Cars that are experiencing more severe wear of the levers may very well not get better to the point you don't notice misfires or poor running.

A lot of the time the problem can be masked by simply unplugging one of the vanos solenoids which renders the vanos and valvetronic in a static state. You won't see or feel any of the symptoms and the code thrown will be stored although not flagged up as a management light. However the downside to this, although it is certainly the lesser of 2 evils is you will more than likely notice lack of power through disabled vanos.

The levers were changed by BMW to a different type from about late 2005 or so (build date), and the whole debacle is coverd under service bulletin SI B 11 02 05. In North America they would do something about it but not here in Europe (as per usual).

Its a very big job to correct and you need a special jig for the cylinder heads so its not really a DIY.

Rather than have you spend oodles of cash on the problem replacing myriads of coil packs, plugs, vanos solenoids etc it may be better to go into a dealership forearmed and with a copy of the service bulletin to have them test in the same way it describes for a proper diagnosis.

I have the same issue on my 645i and i first noticed it as a frien and myself saw one of the solenoid plug wires to a vanos solenoid looked broken or even cut. We found out by reading the codes with INPA and decided we had found an issue and would repair the wiring. Upon repair the car ran fine until the next morning whereupon i experienced many of the symptoms you described.

After extensive misdiagnosis by a main dealer much to my repeated explanations to them and chargrin i found the issue myself through investigation on the internet.

It seems my plug was cut on purpose in order to mask the issue prior to my purchase of the car.

If you do want to pursue a repair may i recommend Steve at Mr Vanos over here in the UK. Whilst not the most insignificant amount of money ever spent it is certainly the cheapest option to remedy the car PROPERLY and he is well versed with the valvetronic system, has carried out the procedure before, and has all of the special tools required.

I hope this is of some help.

houbmw-cm 12-02-2012 09:39 AM


Mine did this and it turned out to just be a bad coil connection. The coil itself was fine, just needed to be reseated. The Variation you have with it running then restarting and running fine sounds about right too. Heat causes expansion and this coudl cause the coil to become seated better and run better, but means there is not enough connection to maintain a solid connection. I had a misfire on Cylinder 8 went down to BMW picked up a new coil, then thought, I'll just push this on better and see what happenes before I actually replace it. Syre enough. She fired up smoothly and ran great.

Hope this helps and this is just some bad connections for you, rather than what gebhardt is describing.

gebhardt 12-02-2012 10:23 AM

Hopefully it will be. But as my dad always said, **** in one hand and wish in the other, and see which one fills up first.

Usually its better to be prepared for the worst and hope for the best.

Given this car is driven about 30k per year it would explain that the symptoms have become increasingly worse in a relatively short amount of time.]

Like i said, usually by disabling the vanos by unplugging a solenoid is an easy way to mask this problem.

Given that this example is particularly rough running and is so more often even when warm, i could not guarantee that unplugging a solenoid would eradicate problems completely (as in rough running and idle issues) although its certainly easier than removing coils about the place and if it did improve, would point to the issues i describe.

I am not here to make rash assumptions or be a happy bearer of bad news, but rather to put people in the picture about a well documented issue by BMW themselves that manifests itself in exactly the way and symptoms you are describing.

Sure, it may be that if this is the issue you do not want to pursue a repair, but to know that AFTER spending another 700 in so called repairs by techs even at the dealership replacing parts that are not needed, is another kick in the stones.

If it were me i would try and unplug a vanos solenoid first to see if the symptoms reduce or dissapear. If not, you can swap out coils and plugs from the cylinders giving you errors and see if the codes jump over to the cylinders you swap into as described above.

Failing that, i think a proper diagnosis to confirm by Mr Vanos etc, but i would say its a 99% certainty its the levers.

Oh BTW, your cat codes are symptomatic of unburnt fuel entering the cat and being picked up by the 02 sensors due to your misfires not igniting the mixture.

Have you looked at the link i provided or indeed the service bulletin (just copy and paste it into google or similar) to see if any of these symptoms correspond with yours?

sharkyclark 12-02-2012 12:49 PM

Hi Herb, Gebhardt,

Thank very much both for contributing, I really do appreciate it.

I have noticed that piece on the intermediate levers in the past, but, given that only 2 of my cylinders have been misfiring consistently, I am hoping that this is symptomatic of a smaller issue, rather than the intermediate levers affecting potentially all of the cylinders?

It has got dark out here early, coz we're in UK winter, so I am pondering going outside and unplugging the vanos first as you suggest gebhardt, to see if that helps. If not, then I'll have to reseat coils if it doesnt when its light out, then its off to see mr vanos I suppose.

OR who wants to place bets on the outcome? If enough people in the forum place and I take a %age of the winnings it'll fund my fix heh heh zzz ok just kidding.

As much as I hate BMW I love the car so even at risk of a divorce, I wanna fix it. But its very important I try and do as much as I can myself, so let's see what I can find out.

Some of the answers will surely be provided by Wednesday this week on the vanos and coils, as I actually have it booked into a BMW specialist (ex-BMW). But if I can check a couple of these things first myself perhaps I'll save myself a visit (although that nasty oil leak still needs fixing...).

gebhardt 12-02-2012 11:20 PM

i really do hope it is a smaller issue such as coils etc. I really do not want to pee on your parade but my suggestion is in line with trying at least to save you as much money as possible during the diagnosis phase.

I can diagnose issues myself and had already come to the conclusion at least that the vanos solenoids were not at issue, nor coils or plugs, as i had already swapped over parts from the offending cylinders with known good ones, and had even swapped vanos solenoids over to be confronted with the same fault codes and issues.

However, when taking it to a main dealer for further advice and asking for tests on GT1 i was stonewalled and told they would carry out there own diagnosis, which i reluctantly accepted. On my return they had swapped out the 2 coils and a vanos solenoid for new parts against my wishes and i was faced with a bill for around 500 to have my car back in the same condition as i took it in with.

I was very dissapointed to be firstly ignored regarding my diagnosis wishes and secondly to have so called techs simply read a code and swap parts out without trying to read deeper into the problem, so much the case with todays techs who think fault codes automatically point them to the problem rather than interpret codes.

I digress. With no access to GT1 i know that Steve from Mr Vanos does have access to this and can tell with a simple test through the diagnostic port if viewed from stone cold, which may save you a few quid rather than sending it to many a specialist or dealer. Perhaps if you suggest the lever issue to your specialist and look at his face when asking, it will give you a good idea if he's heard of it and inspire you with confidence.

The best outcome would be you yourself swapping parts over and finding a fault follows a part, saving you a great deal of heartache and time

Also i was (and still am) experiencing a misfire issue on only 2 cylinders if i reconnect my vanos solenoid, as although the levers are wearing out, it will virtually never do so across 8 cylinders simultaneously. My car has had the issue for the last 12000 miles or so, from about 82K.

Have you checked the tube that runs from the front of the engine to the rear inside the "vee" of the engine for signs of coolant leakage regarding your other issue?

sharkyclark 12-03-2012 05:16 AM

Hi Gebhardt,

This is also my main fear. I have spent so much on it, I don't want to throw money away unnecessarily now. I understand totally where you are coming from. I'll have some diagnosis done on Wed by an independent (without jumping into fixes) of the oil leak, coolant leak, rough idle, and rough running and see where that all leads. And hopefully before Wed I can complete the basic checks myself. Depending on the outcomes, I might contact Mr. Vanos.


gebhardt 12-03-2012 05:48 AM

Any news or idea on location of the leaks (oil and water)?

As in, which side of the engine is it coming from as you look at it, if its traceable at all.

sharkyclark 12-03-2012 06:26 AM

Hi Gebhardt,

Apparently the coolant leak is within the engine (needing cap with seal repair / expanding coolant pipe fix required possibly) but I'll have to go back and check what BMW last told me. Thanks for reminding me, I'll have to check that before Wed. The leak isn't so noticeable as prior leaks I have had i.e. once every 2 weeks I have to top up the coolant a little bit.

Oil leak - apparently was leaking in 3 places (somewhere near alternator, oil filter and oil plug was loose (how does that get magically loose?) ). Oil filter / plug have been taken care of, the major oil leak however being apparently somewhere in the region of the alternator and needs engine removal apparently. So left side of the engine. I have to fill up with 1 to 2 L of engine oil every few days now, so it is pretty severe. I say apparently a lot because at the moment I am relying on everyone else to tell me whats up, hence its time I pay more attention to diagnosing what I can myself from now on.

I had gearbox sump replaced a year and a half ago and topped up. I don't think that is a problem for now.

I'd like to buy some kind of blocks to raise my car up so I can get dirty and start inspecting this stuff, or rent a thing with a pit for half a day. But I really need to be educated about this stuff first, I am a complete newbie. I did download the N62 manual, am reading that, and I do know more than before, but if I walk into any garage, I am like a deer in the headlights if thats the right expression.



carloschicko 11-10-2014 12:56 PM

Hello people, got two problems which I have been told are common on 2005 bmw 6 series (E63).
1. Seat restraint waning and airbag from now where after the car wash people disconnected the socket, I tried clearing from the garage computer. but eventually comes on. : (
2. Vanos intake problem. been told its common too. my 6 has now done 103000 and now all of a sudden making knocking noise and feels like its gonna cut off while driving.
tried asking some of the so called BMW specialists all they talk is 1000s and now it has put me off even touching the car,
any suggestions fellows???

All times are GMT -7. The time now is 09:34 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
© 2001-2015 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms